Check the Gecko forums. Pangea has a forum, Geckos Unlimited is a forum, Repashy has a forum, etc.
There's always Fauna Classifieds as well. (I'm not a fan of kingsnake.com)
Your best bet to find what you're looking for, from a reputable breeder, is one of the gecko forums.
Crested Geckos lose their tails for a number of reasons, but mostly due to stress, from being housed with other geckos, handled when they're stressed out, etc.
Unfortunately, since Cresteds don't grow their tail back, they have "frog butt" for the rest of their lives.
A gecko wagging/wiggling its tail is a sign that it is stressed/aggrivated, & is going to throw its tail.